What must research animals have for scientific findings to be valid and useful?

• A. A large population
• B. Healthy and protected from undue stress
• C. Specific diets
• D. Individual personalities

Answer: (B)

The main idea is that the trustworthiness of scientific findings from animal studies hinges on the animals' welfare. When animals are healthy and not subjected to unnecessary stress, their physiology stays closer to normal, so the responses seen are more likely caused by the experimental variable rather than by stress or illness. Stress and poor health can alter hormones, immune function, metabolism, and behavior, creating confounding factors that distort results and reduce both reliability and relevance to other settings or species. While other factors like how many animals are used or what they eat can influence outcomes, they don’t by themselves guarantee validity. Large numbers don’t fix welfare issues, and strict diets or individual personality differences can introduce additional variability. Protecting animals from undue stress and ensuring good health is therefore essential for producing findings that are valid and useful.